Process for the manufacture of antihalation layers



June 8, 1943. R. BRODERSEN EIAL 2,321,279

PROCESS FORJHE MANUFACTURE OF ANTIHALATION LAYERS Filed July 13, 1940 TRANSPARENT FILM BASE sn/s/r/zEb EMULSION 'IIIIIIIIIIIIIIIIIIIIIIIIIIII ANTI-HALATION LAYER ca/vs/s T/NG OFA DVE STUFF co/vm/m/vc AT LEAST 0N5 CARBOXY aeou 3410 Ms STUFF. BEING ANAHOMAT/C A20 COMPOUND on THE CONDE/VSA TIO/V pnooucr OFA QU/NONE-W/T/l A PHEA/YLENE D/AMINE H/cHA/m EmuuERsh-N-Dusmv' W/LMANNS .9 W fllfiomeg Patented June 8, 1943 PROCESS FOR THE MANUFACTURE OF ANTI- HALATION LAYERS Richard Brodersen, Dessau, and Gustav Wilmanns, Wolfen, Germany, assignors to General Aniline & Film Corporation, New York, N. Y., a

corporation of Delaware Application July 13, 1940, Serial No. 345,368 In Germany August 23, 1939 3 Claims.

This invention relates to the manufacture of antihalation layers.

In most cases it has been necessary to apply antihalation layers to photographic materials. Byusing a binding age'nt they are mostly applied to the rear of the support for the photographic emulsion in such a way, that they can be readily decolorized and removed therefrom. This procedure is connected with certain disadvantages: The thickness of the film is increased, the developer cannot completely be used up for processing, also the emulsion layer may be color-tinged and the like. Besides meeting the optical requirements, the antihalation layer must be as thin as possible, mechanically strong and also water-repellent, but on the other hand must be readily soluble in the developing baths with dyeing the developer or reducin its developing power. To a certain extent the latter happens for instance with the soluble layers described in U. S. Patent 2,161,788, as they reduce the alkali contents of the developer, in ordertobecome soluble themselves.

The afore-mentioned requirements are fulfilled by layers consisting of dyestufi only which combine good adhering and film-forming capacity with insolubility in water and excellent solubility in the developer.

This invention has as an object the preparation of new and useful antihalationlayers which are free from the above mentioned disadvantages.

A further object of the present invention is the preparation of antihalation layers possessing good film-forming capacity and being readily soluble in the developer.

These and other objects will become apparent from the following description.

As a general rule it has been found, that dyestufis containing carboxyl groups are the ideal representatives of. this group. Dyestuii's without groupings efiecting solubility in the' developer spontaneously on account of the carboxyl group-- ing without leaving traces of the dyestufl on the I support.

(COOI-LSO3H) are not suitable, as they are very hard to remove. The comparison of quite a number of normal dyestufis containing sulfo groups with the corresponding carboxyl dyestuffs shows furthermore the general importance of the latter I grouping for the aforesaid antihalation purposes: The layers from sulfo dyestuffs, in so far as they can be prepared as a continuous layer, are always destroyed under a soft mechanical stress, especially if they are touched by moist hands. A support for the photographic emulsion, dyed by a carboxyl dyestuff, can be removed from the dyestufi only by rough mechanical means. The dyestufis which naturally must show suitable solubility, form, if properly applied, no crystals, but an extremely fine film, the latter being firmly connected with the support for the photographic emulsion. When such photographic material is brought into the developer, the layer dissolves Which dyestufl groupings are to be used depends on the special purpose which is to be attained. If necessary, also two or more dyestuffs may be combined in one layer.

The literature reveals that two or more examples of the use of dyestuffs containing carboxyl groups are already known. It relatesonly, however, to the special application of a dyestuif without recognizing the general validity of the principles described.

The following are given as examples of the afore-mentioned rule:

(A) A comparison of the layers from' (a) Malachite green (b) Chrome green (0) Helvetia green shows that (a) Does not dissolve in the developer (b) Yields a continuous layer, is water resistant, and dissolves spontaneously in the developer (0) Yields a water soluble, vulnerable layer which can be rubbed oil easily. Y (B) A comparison of the three yellow-red dyeshows that. their properties cgrrespond to those listed in Example A.

' (C) Layers from I HOOQCHON=l 8 v (b) I onlcoon Tmcoon e 3 l 1 C] (c) ICalls F lls NaSO on N Arr-on so also have the properties of (a); (b) and (0) respectively as in Exampl A.

(D) A comparison of 02115 02H; y (b) $113 (3H3 Qi- 6Q Cl C OOH C O OH I CzHa CzH (C) ClHa CH:

NaSOaO-N- WTO-SO:

N 02H: Ca a demonstrates that the properties of these dyestufis correspond exactly to those of th above mentioned rule.

Example I 10 grams chrome green are dissolved in 500 cc. alcohol and i 500 cc. propanol and applied to a. support from acetyl cellulose. The layer, Which is mechanically resistant and insoluble in water, dissolves readily even in a borax developer.

Example II 10 grams of the dyestufi CH: CH: O 00011 C] N (hHs CiHl are dissolved in 1000 cc. alcohol and applied to glass-plates in a known manner. Theviolet antihalation layer thus obtained adheres firmly and does not dissolve under the influence of humidity.

Example III 10 grams chrome green and 5 grams dyestufl:

are dissolved in 500 cc. alcohol and 500 cc. propanol and then applied to an acetyl cellulose film. The layer thus obtained, even when wet and in contact with a photographic emulsion does not adhere to it.

Example IV 12 grams of a dyestuff of the following constitution CzHs

are dissolved in 1 liter alcohol. This solution is applied to glass-plates, which may be used for the production of panchromatic photo plates.

What we claim-is:

1. A photographic material comprising a support, at least one light-sensitive emulsion layer and an antihalation layer consisting only of a thin film of at least one dyestuff containing in its molecule at least one carboxyl group' and selected from the group of dyestuffs consisting of aromatic azo compounds and condensation products of a quinone with a phenylene diamine.

2. A photographic material comprising a support, at least one light-sensitive emulsion layer, and an antihalation layer consisting only of a thin film of a dyestuif having the following for- 3. A photographic material comprising a support, at least one light-sensitive emulsion layer, and an antihalation layer consisting only of a thin film of a dyestufl" having the following formula RICHARD BRODERSEN. GUSTAV WILMANNS. 

